1. Field of the Invention
The present invention relates to an image processing apparatus for compressing digital data.
2. Description of Prior Art
In an image processing apparatus for processing digital data, input image data is once compressed and stored in a memory device. When the image is outputted, the data is read from the memory device and expanded to the original image data. In this case, a plurality of sheets of the image data are stored in the memory device in the order of the coding.
When image data are stored in a system where a plurality of sheets of image data are subjected to variable-length coding and stored in a memory device, it is desirable that code data of as many sheets as possible is stored in a limited memory size. For this purpose, there is a need for an efficient memory management technique and a random access technique for accessing a desired page in the code data of a plurality of pages stored in a compression memory. However, it is generally difficult for the variable-length coding to know the size of the coded data before the coding.
In the above-described image processing apparatus, a sequence of image data of a plurality of pages ca be efficiently stored in the memory device. However, when only the data of a specified page in a sequence of the data is erased to store new data in the erased data area, the memory device cannot be managed because the size of the code data to be written newly is not known, and the data cannot be written. Therefore, it is desirable to efficiently store image data of a plurality of pages of an unknown data size in a memory device.